new nubm49 diode isn't that good

New member

hello everyone 2 days ago i received my nubm49 diode for testing and the results aren't that good as we have better choices than this diode.

first of all the divergence out the gball is like flashlight exactly like nubm42 i have tested in my previous post,while i could get a good output out of the nubm42 around 7w using some active cooling this diode doing around 6w and around 5.5w peak at room temperature. i don't see any pros for someone to get this diode over the previous models.

ps: RedCowboy i remember that your power testing results on your nubm42 was different that mine and looks exactly like the nubm49 i just tested,the seller could have messed up the diodes on you or even me,i also had a problem recently with him,i bought 1 of the newer green diodes 525nm and he sent me a nugm01:tsk:

Well-known member

I recently received my 1st nubm49, testing it at room temp ( 72 F ) @ 4.5a with the GBall intact and a backwards G2 followed by forward G2 I get 4.9w.......so in the interest of science I popped the can off and tested with just a single G2 @ 4.5a and got 5.4w which is about right as the GBall and extra G2 eat about 5% each.

For reference a NUBM44 will do 5.2 - 5.5w with a 3 element at 4.5a and 6.5 to 6.9w with a G2.
This puts the 49 a solid 1 - 1.5w behind the 44

I posted a video testing your GBall preserving method with the backwards G2 plus 3 element set up and it fixes the problem nicely without removing the GBall, there is an additional 10% power loss over simply removing the GBall as we leave the GBall in place and add a G2, that is removed GBall with 3E only vs. intact GBall plus G2 and 3E, the difference being the GBall and backwards G2 which are both 94-95% efficient, it's well worth the 10% as the diodes will degrade at an accelerated rate if the can is removed.

Lifetime17 made me some nice 12mm wide brass couplers, 16 and 18mm length work well for G2 and 3E final focus with a backwards G2 middle and the GBall primary, being 12mm wide you can slip the module and coupler into a heat sink once assembled.

New member

i had this problem with Techhood from ebay,also from the same seller me and RedCowboy had different results on our nubm42 diodes(seems to be different diodes mostly something like 1 nubm42 and 1 nubm49) that got from the same seller.

I recently received my 1st nubm49, testing it at room temp ( 72 F ) @ 4.5a with the GBall intact and a backwards G2 followed by forward G2 I get 4.9w.......so in the interest of science I popped the can off and tested with just a single G2 @ 4.5a and got 5.4w which is about right as the GBall and extra G2 eat about 5% each.

For reference a NUBM44 will do 5.2 - 5.5w with a 3 element at 4.5a and 6.5 to 6.9w with a G2.
This puts the 49 a solid 1 - 1.5w behind the 44

I posted a video testing your GBall preserving method with the backwards G2 plus 3 element set up and it fixes the problem nicely without removing the GBall, there is an additional 10% power loss over simply removing the GBall as we leave the GBall in place and add a G2, that is removed GBall with 3E only vs. intact GBall plus G2 and 3E, the difference being the GBall and backwards G2 which are both 94-95% efficient, it's well worth the 10% as the diodes will degrade at an accelerated rate if the can is removed.

Lifetime17 made me some nice 12mm wide brass couplers, 16 and 18mm length work well for G2 and 3E final focus with a backwards G2 middle and the GBall primary, being 12mm wide you can slip the module and coupler into a heat sink once assembled.

thanks paul its my honor to be part of this great community,i would never imagine that i would chose a so weird and rare hobby in my life and i would never make it this far without this community. some of you are the legends here :bowdown: im far behind that :evil:

Well-known member

I've had pretty good luck with Techhood and their other companies. I hope they haven't deviated from good customer service as I just bought an NDG7475 from them and it has shipped and is on the way to me now.

Well-known member

You will be happy with it, but remember we talked about the 1st one ( Advertised NDG7475) I bought possibly being a ndg-700 because of the current in vs. the output.

However variables do exist so this test is not 100% conclusive, but....

I am very happy with my 100.00 1w 520nm from techhood, it arrived with virgin clean pins.

I am driving it with a 1.8a X-drive, batteries are 2 x 26650's IMR and I am getting 778mw with a 3 element green AR coated lens.

In DTR's test using a G2 lens at 1.8a on his PS his readings were 1187mw for the ndg7475 and 1026mw @ 1.8a for the ndg-700

If the diodes raw output loses 5% through the G2 and 30% through a 3 element then the difference between the two lenses is roughly a 25% additional loss.

So 25% from 1187nm leaves 896mw and my reading was 778mw .......is my diode a 7475 or 700 ?

So 25% from 1026mw leaves 770mw and my reading was 778mw.......this fits the bill.

It appears I may have received a brand new ndg-700 in place of my ndg7475, however the 100mw difference is no big deal and I am happy, I would buy another if I can get it for the prices I have seen recently, next diode I will drive around 2.25a

---Edit---

I also have a 525nm GBall that I won for under 50 bucks, it was listed as refurbished and with the Gball removed I am driving it with a 1.8a X-drive and it wears a 2 element, it's doing right @ 800mw and has held up well, granted it's not getting much total runtime but for the price I can't complain.

Well-known member

I am more concerned about the shipping now. It went out by speedPAK, an eBay only shipping option that cannot be tracked any other way than eBay. There are dozens of complaints about this shipping option as the tracking doesn't update in time for you to know when it is coming. And people have waited as long as two months to receive their items if they show up at all. I agree that $84.00 is still a good price for the 700 if it turns out to be that. Does anyone know much about this new shipping option from eBay?

New member

i have bought an ndg7475 from him in the past and looks like it is the right thing and not the lower ndg700,i could push it up to 13xxmw,it wasn't reaching over 1400mw but those number are already in the ndg7475 diode range.

about this shipping method i don't know,i mostly use the free and slow shipping.

Well-known member

I didn't ask or pay for speedPak shipping. It is a new idea of eBay's that was touted to make shipping from Asia, China mostly, faster. Unfortunately, it is only tracked by eBay and no one else. I have read the reviews of it and I am not pleased so far. I will have to see if I can get tracking updates and receive my diode within 17 days. That was normal for the Epack shipping these used to have.